Solid state relays generally employ an isolation device between the input device or control signal and the relay. One type of isolator is an opto-isolator which uses a light source and a photodiode to isolate the control circuit from the relay. These have a number of shortcomings. They are slow and they are difficult to integrate with the solid state relay switch devices in the fabrication process for integrated circuit chips. Further multi-channel designs introduce a cross talk problem between the light emitters and detectors. Another type of isolator is a transformer isolator that passes the control signal from the primary to the secondary and uses a trigger circuit to respond to a feature e.g. a rising edge of the a.c. signal from the secondary to generate a current to operate a triac switch constituting the relay. One problem with this is that a triac is generally implemented as a discrete element because it is difficult to fabricate in an integrated circuit chip process e.g. CMOS. Further a triac requires a high trigger current e.g. 30-50 ma which requires a larger transformer not readily implementable in an integrated circuit chip process. In addition these transformers tend to be slow: not able to switch on and off quickly because of their size and higher inductance. Further, when a triac is working to an inductive load, a snubber circuit must be used to address the turn off delay caused by the induced current through the triac from the collapsing field. Triacs also have a relatively high forward resistance which makes them less than ideal for low voltage, high current loads.